Conventionally, as such a kind of housing, there is a known housing for a master cylinder device in a vehicle brake system for controlling a brake fluid hydraulic pressure applied to wheel brakes of a vehicle (automobile) (for example, Patent document 1).
The housing is mounted on a base in which a master cylinder and/or hydraulic passages are provided thereinside to perform roles of housing parts and/or electronic parts such an electromagnetic valve for opening and closing the hydraulic passage, a pressure sensor for detecting the brake hydraulic pressure, etc. Accordingly, the housing is configured to have a capacity able to house these parts.